scope:

This standard specifies the engineering methods used to measure noise produced from motorcycles in ordinary urban traffic conditions.

The provisions of this standard are designed to reproduce the level of noise produced from major sources of noise during normal transit in urban areas.

The measurement method is prescribed such that expectations for ease and convenience can be met within limitations that will enable vehicle operating conditions to be reproduced as much as possible.

This test method requires an acoustic environment that can only be obtained by extensive free space. Such conditions are normally used in the following cases:

- Vehicle model certification tests

- Measurements during manufacturing stage

- Measurements at authorized test sites

Note 1: Results obtained with this test method will be objective measurement values of noise produced under prescribed test conditions. However, it is necessary to take into account the fact that subjective evaluations of automobile noise do not simply correlate with the values indicated by a sound level meter. Noise is strongly related to individual sensibilities, physiological conditions, and cultural and ambient conditions, so there can be a large variation. For this reason, it is not an effective parameter for indicating specific vehicle conditions.

Note 2: It should be noted that sampling inspections of randomly selected vehicles are rarely performed in an ideal acoustic environment. If measurements must be taken from a road whose acoustic environment does not meet the requirements prescribed in this standard, it should be understood that the results obtained would deviate somewhat from the results that would have been obtained under the prescribed conditions.